From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7BC6C46470 for ; Mon, 13 May 2019 16:02:48 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7792D2168B for ; Mon, 13 May 2019 16:02:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="QnhBLyrl" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7792D2168B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 154A46B0280; Mon, 13 May 2019 12:02:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 106E06B0282; Mon, 13 May 2019 12:02:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F10646B0284; Mon, 13 May 2019 12:02:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) by kanga.kvack.org (Postfix) with ESMTP id B91766B0280 for ; Mon, 13 May 2019 12:02:47 -0400 (EDT) Received: by mail-pf1-f198.google.com with SMTP id k22so9835507pfg.18 for ; Mon, 13 May 2019 09:02:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:mime-version:references :in-reply-to:from:date:message-id:subject:to:cc; bh=eCJScE0b+VNTPBqsRt3H1dcVApPbPwSgCSFEuoANhc8=; b=Y55b7DiaHOdJnMHhtd/c9qJdqikzPE94sXDJQDWYdwsfdHnjDncS7myAJHNT9ZIZSO Om4RJAYaeuCGpHd8yvUYBfexT4kx3cXhcbEMD/ICVDsDMzs0N5zrtvXgnMyDiJWX/nol Ijgd6DJTHi9LtfU2p/rM/RX1erKP/fEz9FPyvVbSbYXESlp5OGi+4Ut3OH5A5Lct7o8j ZbZXhoJ+IbiJtKejNDhTUyU+Wm3J/BnwI8pLiagg/OZy7MmODlictYM6XgcYE9pZK1U5 Pw33tB38DpCkslcHm/XEaFF5j4HocnVEtd69RF4QD2Pjqg9VTdhgQPfGhNbYTiW0K1jL jIbw== X-Gm-Message-State: APjAAAXpHTGR74tAunhDTNRlMsPEpO0U2xxp/KN5e5DNa7vl+0lrKdpB Xpph7SbF6VoMDLvOhAq0+3/G0Ki+SNzzJb+g7ZqduabdsglzX5fLPp9ytKE+mkC62WFHkX+Dui9 ZefMZ1nWlB9edGLRp+NIYCF0PJJ4kHl7zr1T7C5LzfvWlLawLUBE+6Iz9JpYGfebZQw== X-Received: by 2002:a62:4595:: with SMTP id n21mr34777447pfi.79.1557763367459; Mon, 13 May 2019 09:02:47 -0700 (PDT) X-Google-Smtp-Source: APXvYqwPYOxXxzfitGhiWQsDBbjPu5mmPqR47fusm4yuoa9DKMYaPo4yKkPplVPWv9mL7XaPqKfL X-Received: by 2002:a62:4595:: with SMTP id n21mr34777316pfi.79.1557763366635; Mon, 13 May 2019 09:02:46 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1557763366; cv=none; d=google.com; s=arc-20160816; b=K6oD4RgmvexmYHkCiESu2u+Quzs0L+H4NzERXmkVSxn+OqAOkuhoD59RPbKVlh98Jc wa1CYFV00nAhYKHsFfWiJh5Ts6xq/1Pqs3JVbA5EMahzI1CgfDKGUNcg6ixP3juMPpFp by/ccp9ckvZpGrQvt6m62N3KDi33M77/OsaUvcdZrKxaX9pHySp1Q5ci5SgHJtKalqWs PH6wpHJ1fj5nFaDGCXFZR2lAc7Rc5RyQCbXhpPSOEde1BxzcNfMXTNM4ftkseZ5BFk48 TjTvtI5zTro15zViX+LxsbzNPTwfFehzodXlEdjZvuREme8PeTwO6gUn7LU+/nrmG6/S WC6g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:dkim-signature; bh=eCJScE0b+VNTPBqsRt3H1dcVApPbPwSgCSFEuoANhc8=; b=btsDXjjepyk0OWFBpwLuhpNKUj3/3YOlqVW0cvQEhs2CZ8SupF7n+XTyQmy4vvO6ZZ Xlve5DgpXJ6eDjF7B9LoVE1cKk3V+UZzeDJ6mRiNXXlN/ftC/F8AVhtlUCUt/b4vb3xm PwPpcujPK/xQWrwCm1XGJH/ydEttaRZ9nnvZxm0Ub6hvuT8gMC3HrS98m6WGuox0nBo+ 23TP+mj4mBRKR0KYTxR3WICsGgWBtKdwaMtUcchrxpBFX+t7rO8L4R3wUc+hTzVYNVfg 3LCJ1Ue+EsMQ8jyzd7nbH/6f8RNtLsDBm1LptwBjgBlRlre+q3nsxO/N7eepwiPr5Xd6 W1Qg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=QnhBLyrl; spf=pass (google.com: domain of luto@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=luto@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from mail.kernel.org (mail.kernel.org. [198.145.29.99]) by mx.google.com with ESMTPS id 3si17679359pgt.305.2019.05.13.09.02.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 13 May 2019 09:02:46 -0700 (PDT) Received-SPF: pass (google.com: domain of luto@kernel.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=QnhBLyrl; spf=pass (google.com: domain of luto@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=luto@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from mail-wr1-f50.google.com (mail-wr1-f50.google.com [209.85.221.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1731E21881 for ; Mon, 13 May 2019 16:02:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557763366; bh=beoZx4frclCxoXSfTxDXkTuSz0AY0hIAwe1mG3lYD+0=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=QnhBLyrlFAFdFMdYGjrxtpZTRix4ohkczb2rqgQsWALhgFd6D7tiD8w3qEuQjKa4t 6gACJ1mq+rjkrjjgv78C9L1ngGrELfh60U9CNvxeFR0bF4yIiw25vABiO2v6YO8nwh 2BOKdf6lHrzPUcK3M8mxJ2O4+dZiPBseqIuRUnko= Received: by mail-wr1-f50.google.com with SMTP id w12so15940309wrp.2 for ; Mon, 13 May 2019 09:02:46 -0700 (PDT) X-Received: by 2002:adf:fb4a:: with SMTP id c10mr17614362wrs.309.1557763364695; Mon, 13 May 2019 09:02:44 -0700 (PDT) MIME-Version: 1.0 References: <1557758315-12667-1-git-send-email-alexandre.chartre@oracle.com> <1557758315-12667-25-git-send-email-alexandre.chartre@oracle.com> In-Reply-To: <1557758315-12667-25-git-send-email-alexandre.chartre@oracle.com> From: Andy Lutomirski Date: Mon, 13 May 2019 09:02:33 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC KVM 24/27] kvm/isolation: KVM page fault handler To: Alexandre Chartre Cc: Paolo Bonzini , Radim Krcmar , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Dave Hansen , Andrew Lutomirski , Peter Zijlstra , kvm list , X86 ML , Linux-MM , LKML , Konrad Rzeszutek Wilk , jan.setjeeilers@oracle.com, Liran Alon , Jonathan Adams Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, May 13, 2019 at 7:39 AM Alexandre Chartre wrote: > > The KVM page fault handler handles page fault occurring while using > the KVM address space by switching to the kernel address space and > retrying the access (except if the fault occurs while switching > to the kernel address space). Processing of page faults occurring > while using the kernel address space is unchanged. > > Page fault log is cleared when creating a vm so that page fault > information doesn't persist when qemu is stopped and restarted. Are you saying that a page fault will just exit isolation? This completely defeats most of the security, right? Sure, it still helps with side channels, but not with actual software bugs.